Like our other downfire boxes, this one also
moulds around all the bracing on the floor of the truck. Even the large
brace to the right side of the hump. There are no modifications required
to install these boxes. Simply lift up the seats, set the box in
place. It's so easy, you will be impressed. We certainly
are. Fits all years of Avalanche. No other box on the market will
fit this nicely and hit this hard for this price.